During the flight, the passengers and crew are generally confined to a cabin located above the cargo bay. During a typical flight on a passenger airline, each passenger may be required to remain temporarily in their seating location. Each seat may have safety features that are designed to protect the passenger. For example, each seat may be associated with a floatation device that the passenger can access in the event of a water landing. In various examples, the seat may include a seat belt that the passenger may be required to wear, at least during taxi, take off, and landing (TTOL). The seat belt may, for example, protect the passenger in the event of a sudden deceleration due, for example, to the aircraft impacting against a stationary object and/or sudden drop in altitude due to turbulent conditions.
Head Injury Criteria (HIC) requirements are provided, for example, by the Federal Aviation Administration (FAA) to establish standards in passenger protection in passenger aircraft cabin design. Certain HIC requirements are set forth in 14 CFR 23.562, which is incorporated herein by reference. The HIC requirements, for example, result in clearance requirements within a head impact zone to reduce likelihood of passenger concussion in the event of an emergency such as rapid deceleration. Further, the requirements specify a measurable HIC number resulting from, for example, a head impact against objects that are within the head impact zone of a passenger, such as a fore passenger seat or a partition. In this manner, should a passenger's head impact an object such as the forward backrest of the fore passenger seat, the force of the impact is absorbed at least in part through the backrest design.
In some aerospace safety testing applications, a head injury criteria (HIC) may be evaluated over the period when the head of the anthropomorphic test dummy (ATD) is in contact with any structure on the aircraft interior. Injury may be defined as any HIC value exceeding the threshold value of 1000. The HIC may be one of the injury criteria by the General Aviation Safety Panel (GASP) to be considered in the design and certification of aircraft seats and restraint systems.
Typical civilian aircraft passenger seats have historically been oriented facing forward in longitudinal alignment with the aircraft fuselage and passenger cabin. More recently, air carriers have begun installing “suites” in premium and business-class cabins. These suites may include a seat that lowers and extends into a sleeping surface, one or more tables, ottomans, electronics and storage compartments. Airlines may utilize the limited space in an aircraft cabin, by orienting seats at an angle oblique to the longitudinal axis of the aircraft cabin. This orientation allows seats to be staggered or aligned in the oblique angle. Seats may be angled toward or away from adjacent seats to permit ease of passenger interaction or to permit a degree of privacy to adjacent passengers by placing the passenger's normal field of view away from the adjacent passenger.
Standards bodies are developing testing and safety standards associated with passengers who will not be seated forward in an emergency. Proposed standards, for example, are provided in the “Performance Standards for Oblique Facing Passenger Seats in Transport Aircraft” by the Aircraft Seat Committee, International, developed Dec. 14, 2016 and pending FAA and EASA approval prior to publication, which is herein incorporated by reference in its entirety. The Federal Aviation Administration (FAA) has issued a circular entitled “Dynamic Evaluation of Seat Restraint Systems and Occupant Protection on Transport Airplanes,” Advisory Circular AC 25-562, dated Jan. 10, 2006, which is also incorporated herein in its entirety.